Reusable retentive closure for containers



Oct. 9, 1956 J. w. SOFFER ET AL 2,755,960

REUSABLE RETENTIVE CLOSURE FOR CONTAINERS Filed July 27, 1953 INVENTORJACK W. SQFFEER 8 DONALD M. MWTERMAN j Z W,

ATTORNEY REUSABLE RETENTIVE CLOSURE FOR CONTAINERS Jack W. Solfer, St.Louis, and Donald M. Kitterman, Kansas City, Mo., assiguors toDevelopment Research, Inc., St. Louis, Mo., a corporation of MissouriApplication July 27, 1953, Serial No. 370,489 Claims. (Cl. 222--182)This invention relates to reusable retentive closures for containers andspecifically to molded plastic protective closures employed on steeldispensing containers to avoid inadvertent tilting of the dispensingvalves and accidental discharge of the container contents.

An objective of the present invention is to provide such protectiveclosure which is relatively difiicult to remove from the container thefirst time such removal is attempted, but which may be readily removedon reuse. The original retention of the closure to the container mustoffer such resistance to removal that the user may be confident that thecontainer has not theretofore been opened.

After the container has once been opened, it is preferable that theclosure be readily removable, and pos sess only enough retention toavoid being dropped off or dislowdeg by chance physical contact.

A further object of the invention is to provide a reusable retentiveclosure which may be originally removed from the container to which itis aflixed either by twisting or prying.

A further purpose is to provide retentive lugs integrally molded intothe skirt of a plastic closure, which lugs are automatically shaved offon removal of the closure, the extent of shaving being sufficient topermit removal thereafter without substantial expenditure of effort.

A further purpose is to provide a steel-topped container with adownward-presented edge adapted to shave the closure lugs to reducetheir retentive ability the first time the closure is removed from thecontainer edge.

The foregoing and additional objects will be made clear from thefollowing specification and the accompanying drawings (one sheet) inwhich:

Figure 1 is an elevational view of a steel container bearing a closureembodying the present invention.

Figure 2 is an enlarged sectional view taken along line 22 of Figure 1.

Figure 3 is an enlarged sectional view 3-3 of Figure 2.

Figure 4 is a fragmentary sectional view showing a portion of Figure 2to larger scale.

In the embodiment illustrated, a low-pressure steel container 1 (thelower portion of which is not shown in the drawings) is fitted with anannular top 2 by swaging the top 2 radially outward within the neck ofthe container 1. The top 2 is formed by blanking sheet metal, ordinarilysteel, and forming around its edge an annular rim 3 terminating in adownwardly and outwardly rounded camming surface 4, and adownwardly-presented peripheral ledge 5. These parts are shown in theirrespective positions in Figure 2 of the drawings, and are shown enlargedin Figure 4.

In the blanking of sheet metal, the outer edge of the object formed byblanking presents two different portions, a smooth portion formed bycutting or shearing, normally extending about half of the thickness ofthe sheet metal, and a rough sharp edge portion extending the takenalong line States Patent 0 balance of the thickness of the metal andbrought about by the breaking of the part of the partially shearedsheet. Accordingly, the edge 5 possesses two distinct portions, a shearportion 6 which is located nearest the central axis designated a, of thecontainer enclosure, and a break portion 7 which continues outward fromthe shear portion 6 for the remainder of the thickness of the metalutilized in the top 2. The juncture of the break portion 7 with thecamming surface 4, when examined under optical magnification, shows arelatively rough and sharp edge even after tumbling; although not moreso than results from acceptable standards of shop practice. We takeadvantage of this roughness in that it causes the edge to graspretentively into molded plastic materials and on movement to cut orshave them.

At the center of the annular top 2 there is provided along the axis a atiltable discharge valve, generally designated 8, equipped with asealing grommet 9 in which the discharge valve is rockably mounted.

When valves such as the discharge valve 8 are used on containers filledwith fluid and gas, it is necessary that they be protected frominadvertent discharge by tilting. Many types of plastic closures havebeen suggested for this purpose. In the present invention there isemployed a reusable retentive closure, generally designated 10, formedof plastic by injection molding, and having an open'ended annular skirt11 whose inner diameter is greater than the outer diameter of theannular rim 3 of the container top 2. The closure 10 is adapted to beapplied axially downward over the annular rim 3, and to be held thereonby a plurality of circumferentially spaced retention lugs 12 moldedintegrally with the closure skirt. The lugs 12 have inwardly-presentedgrasping surfaces 13 which converge from the upper portion of the skirt11 to .its lower margin 14. The amount of convergence is such that attheir lower, innermost points the radial spacing of such graspingsurfaces 13 from the axis a, is less than the radial distance to theoutermost portion of the annular rim 3. The portion of the retentionlugs 12 which extends inward of the outer margin of the annular rim 3 isshown in Figure 4 to the left of the line bb, and is designated theshave-off portion 15 of the lugs 12. The bottom margins 16 of the lugs12 serve a cam function hereinafter described.

After the container 1 has been filled, the annular top 2 swagedsealingly thereon, and gas inserted through the discharge valve 8, theclosure 10 is placed with the bottom margins 16 of the lugs 12 on theoutwardly rounded camming surface 4 of the top 2. Axial force applied tothe top of the closure 10 presses the bottom margins 16 against thecamming surface 4, deflecting the skirt 11 in the region of the lugs 12to permit its lower margin 14 to pass over the annular rim 3. Thegrasping surfaces 13 of the lugs 12 will pass readily over the roundedcamming surface 4 without damage to the lugs 12.

With the closure 10 in position on the container 1, as shown in Figure2, there is contact between a sharp steel edge 5 of the annular rim 3and the retention lugs 12 of the plastic material of the closure. Theretention of the plastic material to such sharp edged annular lip ispositive; it is readily apparent on manipulating the closure 10. Apurchaser familiar with its firm resistance to movement is assured bythe feel of such positive retention that the closure 10 has nottheretofore been removed.

The user may remove the closure 10 either by axial prying under thelower margin 14 of the skirt 11, or by twisting and exerting an axiallyoutward pull on the closure 10. Whether the force applied is by prying,twisting or pulling, the effect will be to bring the sharp rough edge 5in scraping contact against the grasping surfaces 13, shaving off theshave-off portion 15 of the retention lugs 12. The closure maythereafter be replaced and removed readily, serving as a convenientreusable protective cover for the discharge valve 8, and also serving todisclose the fact that the closure 10 has been removed from thecontainer 1 at least once previously. Thus, any unauthorized removal ofthe closure 10 may be readily detected.

Other embodiments of the invention principles herein disclosed will beapparent to those skilled in the art. Accordingly, the present inventionis to be considered as coextensive with the inventive principles hereindisclosed.

We claim:

1. For use with a steel container having an annular top mounting adischarge valve, such top having a rough downwardly-presented peripheraledge at its outer margin, a molded plastic protective closure adapted tobe applied axially downward over such peripheral edge, the said closurehaving an open-ended annular skirt, the inner radius of said skirt beinggreater than the radius of the annular top of such container, furtherhaving circumferentially spaced retention lugs molded integral with theinner wall of said skirt, the said retention lugs havinginwardly-presented grasping surfaces converging downwardly from theinner wall of the skirt to a radial spacing adjacent the lower margin ofthe skirt less than the radius of such annular container top, the saidgrasping surfaces being adapted to grasp the outer margin of suchannular top along and beneath the rough downwardly-presented edgethereof, and to be shaved to an increased radial spacing by scrapingmovement over the rough edge of the container top incident to removal ofthe closure from the container.

2. In combination with a steel container having an annular top mountinga discharge valve, said top having a rough downwardly-presentedperipheral edge at its outer margin, a molded plastic protective closureadapted to be applied axially downward over said peripheral edge, thesaid closure having an open-ended annular skirt, the inner radius ofsaid skirt being greater than the radius of the annular top of saidcontainer, further having circumferentially spaced retention lugs moldedintegral with the inner wall of said skirt, the said retention lugshaving inwardly-presented grasping surfaces converging downwardly fromthe inner wall of the skirt to a radial spacing adjacent the lowermargin of the skirt less than the radius of said annular container top,the said grasping surfaces being adapted to grasp the outer margin ofsaid annular top along and beneath the rough downwardly-presented edgethereof, and to be shaved to an increased radial spacing by scrapingmovement over the rough edge of the container top incident to removal ofthe closure from the container.

3. The combination defined in claim 2, the annular top of the containerhaving a downwardly and outwardly rounded camming surface adjacent itsrough downwardlypresented edge, whereby on applying said closure axiallydownward, the lower margins of the retention lugs engage said cammingsurface and are spread thereby radially outward suficient to permit thepassage of the lower margin of said annular skirt over the annular topof the container.

4. The combination defined in claim 2, the annular top being formed byblanking, the shear portion of its peripheral edge being on the innerside of the annulus and the break portion of said edge being on theouter side of the annulus, whereby said break portion of the peripheraledge is presented for contact with the grasping surfaces of theretention lugs.

5. A reusable retentive closure characterized by lesser retention onreuse, comprising a molded plastic closure adapted to be applied axiallydownward over a sharp edged annular lip, the said closure having anopenended annular skirt, and spaced retention lugs molded integrallyWith the inner Wall of said skirt, the said retention lugs havinginwardly-presented grasping surfaces converging downwardly from theinner wall of the skirt to a radial spacing adjacent the lower margin ofthe skirt, which spacing is less than the radius of said lip, the saidgrasping surfaces being adapted to grasp the outer margin of said lipalong and beneath the sharp edge thereof, and to be shaved to anincreased radial spacing by scraping movement over said sharp edge andincident to the first removal of the closure from said lip.

References Cited in the file of this patent UNITED STATES PATENTS

